1. Field of the Invention
The present invention relates to a method and device for controlling a headrest of an automotive seat so as to move the same to a non-use position where it is lowered away from the view field of an occupant on the seat, thereby enabling him or her to attain a good view over the seat back.
2. Description of Prior Art
There has been known a movable headrest for an automotive seat, which is moved by a motor under a switching control, so that the headrest body may adjustably be displaced to a use position upon the top of the seat back, where the headrest body erects thereon to readily support the head of an occupant sitting on the seat, or to a non-use position where the headrest body is located away from the forward view field of another occupant sitting on the other seast. Conventionally, in this sort of headrest device, an automatic operation switch is provided for effecting such headrest displacement with one-touch operation, and therefore, a driver on a front seat can operate this switch to cause a headrest on a rear seat to rotate forwardly below his or her backward sight line, to attain a good backward view field over the rear seat and further, an occupant sitting on the rear seat can cause the same displacement of a headrest on the front seat to a point below the forward sight line, by operation of the automatic operation switch, to secure a good forward view field over the front seat. On the other hand, the headrest body can be returned from that non-use position to the use position, through one-touch switching operation of the automatic switch.
In addition to this switch-type headrest control system, there has been known a well-computerized headrest control system, which automatically controls the movement of the headrest upon the seat back of the seat, responsive or sensitive to the degrees of running speed of the automobile, the opened/closed state of its door(s), some partial actions the automobile, or the ambient conditions in which the automobile runs along. According to such system, for instance, assuming that, during driving the automobile, with the headrest located at a use position, an increased speed of the automobile exceeding a predetermined one is detected by a speed sensor, then the headrest is automatically displaced from the use position to a non-use position away form the sight line of a driver or rear-seat occupant, without his or her operation of a partinet switch. Further, let us assume that the automobile is parked somewhere. With the headrest located at the non-use position, an occupant comes up to it and open the door, and such opening of the door is detected by a door switch. Then, there occurs an automatical return of the headrest from the non-use position to the use position upon the top of seat back, thus standing ready to support the head of the occupant. Accordingly, whenever entering the car, the headrest is always located at the use, head-supporting position that gives no hindrance or interference against the occupant intending to climb onto the seat.
However, such highly improved headrest control system has been solely directed to the displacement of the headrest between the use and non-use positions, and not designed to extend care towards an occupant on the assistant's seat next to the driver's seat as well as a rear-seat occupant on the rear seat. That is, the system does not permit theose occupant to effect the displacement of the headrest between the use and non-use positions and adjustment of the same in fore-and-aft position upon the seat back, as a result of which, occupant, excepting the driver, can not attain a desired position of the headrest for taking a better seating posture. Moreover, there would be such trouble that the displacement of the headrest to the non-use under switching operation of the automatic operation switch is to be interrupted by a signal from the door switch being turned on due to the opening of the door, and the the headrest is moved back to the non-use position against the wish of an original operator.